class MyMath:
    def add(self, a, b):
        return a + b

    def minus(self, a, b):
        return a - b

    def mul(self, a, b):
        return a * b

    def div(self, a, b):
        return a / b

    def root(self, a):
        return a ** (1 / 2)



class Worker:
    profession = 'Internet'
    def __init__(self, name):
        self.p = name


class FinanceWorker(Worker):
    department = 'finance'

class DevelopWorker(Worker):
    department = 'development'

class ServiceWorker(Worker):
    department = 'service'

a = FinanceWorker('Alice')
print(f"{a.p}在{a.profession}的{a.department}部")

b = DevelopWorker('Barbara')
print(f"{b.p}在{b.profession}的{b.department}部")

c = ServiceWorker('Carl')
print(f"{c.p}在{c.profession}的{c.department}部")